Well there was some guild that got hold of the http://www.wowpedia.org/Martin_Thunder weapon under the ulduar-toc times, kiting world bosses to citys, like kazzak, he hade some aoe I think that healed him + made him stronger and a gm had to reset/kill him.

BUG: The one that pissed me off the most over the years was the "You do not have permission to loot that corpse."
EVENT: Obviously Blood Plague world event, it was even studied by scientists that study infectious disease.
EXPLOIT: Probably the Arathi Basin jumping over the gate and capping points before the game started.

BUG: The one that pissed me off the most over the years was the "You do not have permission to loot that corpse."
EVENT: Obviously Blood Plague world event, it was even studied by scientists that study infectious disease.
EXPLOIT: Probably the Arathi Basin jumping over the gate and capping points before the game started.

The Blood Plague never really was an event more akin to a bug. That the spell could exist outside of ZG.

I remember in one of the TBC prepatches (may have been PTR) Warriors could stack Rampage infinitely by buffing it, zoning, buffing it again, zoning etc. I tried this, it was great fun to one-shot Lethon with like 3million AP.

-in 5 man dungeons, Arms Warriors again are the weakest link in the chain as they require 3X amount of healing as other classes and therefore die much more frequently and receive less healing in general, as with the amount of mana spent to keep an Arms Warrior alive the healer can heal all other members and himself.

Ha, if we're counting PTRs, then the no-cooldown Typhoon definitely qualifies. Boomkins running around bgs with macros that had /cast Typhoon repeated until the character limit - if they didn't oneshot you, the fall from the stacked knockback effect would finish you off.

Oh right, that time some guys used some program or something and went rampage in major citys one night and killed everyone and everything, was just few months ago, was on the front page here even, donno what everyone called it tho.

Event:
While not in game, the patch 2.3/2.4 (Can't remember which) Retribution rebuff changes when Blizzard failed to aknowledge the need for threat reduction and EU forums rose in righteous fury, making entire official forums spammed with topics of "Threat reduction?" and "Threat reduction" replies to any topic not related. In less than 24 hours threat reduction was modified into one of the existing talents with Blizzard adamantly claiming "No, the uproar had nothing to do with it! Serious!"

Bug:
In 4.3 a bug with Paladin seal caused Retribution damage to triple at the very least.